<html >
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <form>
        <p>
            <label for="uname">名字：</label>
            <input required type="text" id="uname" name="username">
        </p>
        <p>
            <label for="email">邮箱：</label>
            <input type="text" readonly id="email" name="email">
        </p>
        <p>
            <label for="tel">电话：</label>
            <input type="tel" readonly id="tel" name="tel">
        </p>
        <p>
            <button type="submit">提交</button>
        </p>
    </form>
    <script>
        var form = document.getElementById("form");
        form.onsubmit = function(e){
        if(tel>=13000000000<20000000000){
        }else{
            alert("手机号1非法")
        }
        }
    </script>
</body>
</html>